Grasshoff, Gerd Max Planck Fellow Computational History of Science, Max Planck Institute for the History of Science, Max Planck Society;
https://www.zenodo.org/record/3269732#.YILQd-tCSks (Any fulltext)
Grasshoff, G., & Bier, S. (2019). Database of Abstracts in Publications on Exoplanets from the NASA Archive. Zenodo, 05.07.2019. doi:10.5281/zenodo.3269732.